The present invention relates to a process of forming the bottom of a metallurgical container, especially the bottom of a converter for refining hot metal.
Certain refining processes of a bath of molten metal, especially liquid hot metal, consist of combining with blowing oxygen from the top of the metallurgical container into the bath of molten metal, blowing a gas through the bottom of the container in order to obtain a mixing of the bath of molten metal during or after the blowing with oxygen. Such a process is especially described in the French Pat. No. 2,322,202. The gas, introduced through the bottom of the container, is usually an inert gas such as nitrogen or argon. The introduction of this neutral gas is carried out by means of refractory elements permeable to gas arranged in the bottom of the container.
In this case, the bottom of the metallurgical container is constituted in the following manner: It comprises, in succession, on a metal base, at least one layer of refractory material, a first layer of refractory bricks, a so-called layer of security, then a second layer of refractory bricks, a so-called wearing layer, in which are incorporated a plurality of refractory elements permeable to gas and spaced from each other.
The refractory elements permeable to gas are elements such as for instance described in the French patent application Nos. 79/10.445 of Apr. 26, 1979 and 80/0.2905 of Feb. 8, 1980 in the name of the present inventors. These elements are generally constituted by an assembly arranged and joined by refractory non-porous plates placed side-by-side without being joined by a fluid-tight material. The clamping and the cohesion of these plates is assured by hooping by means of a metallic envelope, whereby a closure plate completes the metallic envelope to assure the fluid-tightness of each element with respect to the exterior of the container and a conduit for feeding a gas under pressure is fixed in an air-tight manner to each closure plate to be connected to a gas distribution channel for blowing gas under pressure through the gas-permeable element.
It has been ascertained, that in a bottom of a metallurgical container constructed as described above, the elements which are permeable to gas deteriorate rapidly and must be replaced.